JPH0754766A - Switching valve mechanism for hydraulic machine - Google Patents

Abstract

PURPOSE:To improve durability of a valve driving part by relaxing a shock due to reciprocating a drive rod in its contact clearance, by a ring-shaped intermediate bearing of light weight arranged between an annular switching valve for switching suction/delivery and the drive rod, in an oil hydraulic piston pump and motor of type not rotating a cylinder block. CONSTITUTION:In a driving mechanism for a swivel type annular switching valve 20 driven by an eccentric shaft 23 for switching each cylinder 5 synchronized with advancing and retracting a piston 7, a ring-shaped intermediate bearing 30, having a suitable clearance between a drive rod 21 inserted to a liquid-tightly slidable drive rod through block 22 and the annular switching valve, is arranged. In this way, the annular switching valve 20 is driven by coming into not direct contact with the drive rod 21 but contact with the ring- shaped intermediate bearing of lighter weight.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a hydraulic transmission, particularly,
The present invention relates to a hydraulic pump, a motor, and a hydraulic continuously variable transmission. (Prior art and its problems) The gist thereof is a cylinder block connected to a fixed or rotating shaft,
A reciprocating hydraulic machine having a plurality of reciprocating pistons which are slidably inserted in a plurality of cylinders provided in the cylinder block, and which is arranged on the end side of the cylinder block in order to perform discharge and suction. Liquid-tightly slidably arranged between a flat plate on which a port is arranged for suction and discharge and another flat plate parallel to the flat plate to perform eccentric oscillating motion so that the port can be connected to the outer peripheral chamber and the inner peripheral of the annular valve. An annular oscillating directional control valve for switching to a chamber has a plurality of drive rods of equal length abutting on the outer surface or inner surface of the directional control valve along the circumferential direction at predetermined intervals and outside the annular drive rod penetrating block. Side or inner wall part is drilled through a hole extending radially and slidably in a liquid-tight manner, and its outer end is an eccentric cam ring provided on an eccentric rotating shaft or an eccentric part provided on a fixed part. Wick cam ring and opposition In a hydraulic machine having an eccentric drive rod that causes the switching valve to swing by the rotation of an eccentric rotating shaft or the rotation of the cylinder block, one end of the switching valve drive rod is located inside or outside the switching valve. The mechanical position is transmitted by sliding the other end to the eccentric cam and performing the eccentric swing motion for switching. However, this drive rod originally abuts against the inner circumference or the outer circumference of the eccentric force mulling and the annular switching valve, but it is inevitably deformed by the hydraulic pressure acting on this annular switching valve, so that it is between the driving rod and the annular switching valve. Requires a certain amount of clearance, but when vibration occurs in the annular switching valve due to the valve function, this clearance causes metal contact with impact between the drive rod and the annular switching valve, causing Since the pressure receiving area is limited, impact wear may occur at the tip of the drive rod and the gap may further increase. (Means for Solving the Problem) The present invention has been devised in order to solve this problem, and its gist is to provide a relatively thin and light intermediate member between the annular switching valve and the drive rod. Since the bearings are arranged and this intermediate bearing receives the same hydraulic pressure both inside and outside, it does not cause elastic deformation and it is possible to keep the gap between the drive rods small from the beginning, and between the intermediate bearing and the annular switching valve is appropriate. By providing such a gap, the vibration generated in the annular switching valve is dealt with by a large effective area of the intermediate bearing, and the vibration generated in the annular switching valve is absorbed to solve the problem of impact contact wear. (Operation) The introduction of the intermediate bearing inserted between the annular switching valve and the drive rod described above prevents the intermediate bearing from being deformed by the pressure, so that the drive rod intermediate bearings are always kept in contact with each other and the impact wear due to the gap occurs. At the same time, since the contact between the intermediate bearing and the annular switching valve is made in a sufficient area, the vibration damping effect due to the presence of the liquid can be obtained and the wear problem due to the impact can be solved. (Embodiment) FIG. 1 shows a structure of a piston type hydraulic machine in which an intermediate bearing is arranged between an annular switching valve mechanism and a drive rod. FIG. 2 shows an annular switching valve section mechanism and FIG. 3 shows an annular switching valve. The enlarged view of the part which arrange | positioned the intermediate bearing in the part is shown. In FIG. 1, a rotary shaft 1 is integrated with a swash plate 2 and is supported by bearings 12 and 13, a cylinder block 3 and a valve block 4.
Is fixed integrally with the casing via a pin or the like.
In the cylinder block 3, a plurality of cylinders 5 extend in the axial direction from the outer end surface of the cylinder block 3 at predetermined intervals along a circumferential direction on a circle centered on the axial center. Pistons 7 are slidably inserted into these cylinders 5 in a liquid-tight manner, and spherical outer ends of these pistons 7 are held by slipper pads 8 so that they can be slidably moved. These slipper pads 8 are retained by a retainer 9, and the sliding surface thereof is brought into sliding contact with the inclined surface of the swash plate 2. An annular switching valve 20 is arranged on a parallel plane formed by the cylinder block 3 of the valve block 4. There is a cocoon-shaped opening of the cylinder boat 6 at the center in the radial direction on the plane on the cylinder block 3 side.
The radial outer end of the is connected to the first external port 33 through the liquid passage 31 provided in the valve block 4 at a predetermined interval along the circumferential direction, and the radial inner end is circular. It communicates with a second external port 34 via a second liquid flow path 32 that is formed in the valve block 5 at a predetermined interval along the circumferential direction. The annular switching valve sliding portion has substantially the same diameter as the pitch circle in which the oval openings of the cylinder boat 6 connected to the cylinders 5 are arranged, and has substantially the same thickness as the radial dimension of the oval openings. An intermediate bearing 30 is inserted on the inner side surface of the annular switching valve 20 having a large thickness, and the inner peripheral side of the intermediate bearing has a plurality of drive rods 21 of equal length at a predetermined interval along the circumferential direction. These drive rods 21 are struck against each other and penetrate through a drive rod penetrating block 22 arranged in the valve block 4 in a radially extending hole so as to be slidable in a liquid-tight manner, and the inner end thereof is provided at one end of the rotary shaft. The tip of the drive rod 21 is in contact with the outer periphery of the eccentric cam 24 provided on the outer surface of the eccentric shaft 23. The eccentric cam 24 is eccentric by Δ along the direction of the neutral line of the inclined surface of the swash plate 2 from the shaft center, and is inserted into the outer periphery of the eccentric shaft 23 connected to the rear part of the rotary shaft. An annular switching valve 20 that is eccentrically movable in synchronism with keeping rotation and is mounted so as to be slidable in a liquid-tight manner.
The cylinder port 6 is divided into an outer chamber and an inner chamber by. The valve block 4 and the cylinder block 3 are joined to each other by a plurality of bolts or the like that extend in the axial direction at predetermined intervals in the circumferential direction. Then, when the rotary shaft 1 is driven to rotate, the spherical outer end of the piston 7 is slidably contacted with the inclined surface of the swash plate 2 via the slipper pads 8, so that the piston 7 reciprocates in the axial direction. At the same time, the eccentric shaft 2 connected to the rear part of the rotary shaft 1
3. The eccentric force on the shaft 3 slides on the cam surface of the eccentric cam 24, and the drive rod 21 reciprocates in the radial upward direction.
The annular switching valve 20 eccentrically oscillates in the cylinder port array portion through the outer periphery of the cylinder port 6 communicating with the cylinder 5 into which the piston 7 in the forward stroke is inserted, and the piston in the backward stroke. By switching the oval opening of the cylinder port 6 communicating with the cylinder 5 into which the cylinder 7 is inserted, the cylinder port 6 is opened to the outer chamber or the inner chamber. The outer chamber and the inner chamber limited by these switching valves are connected to the external port 33 and the second external port 34, respectively.
Thus, the liquid is sucked from the first or second external port 33 or 34 connected to the backward stroke of the piston 7, and the first or second external port 33 or 34 connected to the forward stroke of the piston 7 is drawn. It functions as a hydraulic pump or motor that discharges more liquid. FIG. 2 shows a partial view of the annular switching valve 20, the intermediate bearing 30, and the drive rod 21, and FIG. 3 shows an enlarged view around the drive rod. (Effect of the device) According to the present invention, one end of the drive rod can be stably and closely contacted with the intermediate bearing part, so that the impact wear of the tip of the drive rod part is reduced, and the surface contact between the annular switch valve and the intermediate bearing makes the annular switch valve. The effect of damping the generated minute vibration can be expected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the overall structure of an embodiment, FIG. 2 shows an embodiment of an annular switching valve portion, and FIG. 3 shows an enlarged view of a drive rod and an intermediate bearing portion. Rotating shaft ・ 1, swash plate ・ 2, cylinder block ・ 3, valve block ・ 4, cylinder ・ 5, cylinder port ・
6, pistons 7, slipper pads 8, retainers 9, casings 10, 11, bearing-related parts 12, 1
3, annular switching valve · 20, drive rod · 21, drive rod penetrating block 22, eccentric shaft · 23, eccentric cam · 24, intermediate bearing · 30, first liquid passage · 31,
Second liquid passage, 32, first external connection port, 33,
Second external connection port 34

Claims (1)

(1) In a piston type reciprocating hydraulic machine having a large number of pistons, it is arranged so as to be slidable in a liquid-tight manner between two parallel flat plates, and on a flat surface on the end side of one silicider block. A plurality of drive rods of equal length are arranged at predetermined intervals along the circumferential direction of the annular switching valve for switching a large number of provided cylinder ports to the intake and discharge directions, and the outer or inner wall portion of the annular switching valve is arranged. An eccentric drive mechanism that pierces the inside of a hole that extends radially and slidably in a liquid-tight manner, and its outer end abuts an eccentric eccentric cam ring that is eccentrically rotatable and causes the switching valve to perform an oscillating motion. And an eccentric oscillating annular directional control valve drive mechanism, wherein an annular bearing is inserted between the annular directional control valve and the drive rod contact portion.